Screwdown-lift



Feb-1 0, 1970 -w. W. EIBE SCREWDOWN-LIFT Filed March 25, 1968 Y wmi visib.

Fig. I.

United States Patent U.S. (:1. 72-243 8 Claims ABSTRACT OF THE DISCLOSURE A screwdown-lift capable of rapidly advancing and retracting the screwdowns of a rolling mill.

This invention relates to screwdown-lifts used to drive the screwdowns which position and load the rolls of a rolling mill. It is particularly useful in rapidly advancing and. retracting the screwdowns so that the rolls can be changed in the minimum of time.

A rolling mill is used to make metals into various shapes. It may consist of relatively small work rolls and larger backing up rolls positioned parallel to each other, where backing up rolls are positioned in contact with work rolls when the mill is operating. The rolls are held in position by chocks at the sides of the mill engaging the necks of the rolls. The chocks are in turn positioned within windows in the mill housing so that they can move perpendicular to the movement of the material through the mill and loaded during mill operation by screwdowns. The screwdowns engage the chocks positioning the upper or outermost rolls, usually backing up rolls. Each screwdown has a screw which advances and retracts from a screwdown nut rigidly fixed in the housing of the screwdown as the shaft of the screwdown is driven through a gear train by a power means.

In normal operation, the screwdowns are driven through worm shafts meshed with worm gears which are keyed to the shafts of the screwdowns. Separate motors are positioned to drive the Worm shafts through pinions and driving gears keyed to the worm shafts. The motors are also positioned so that their shafts are on a common axis and are coupled by a clutch means. In this Way the screwdowns can be operated independently to separately adjust the loading of the screwdowns on the rolls on each side of the mill or can be operated in unison by actuating the clutch means to couple the shafts of the motors.

This conventional screwdown device is old and well known and is quite satisfactory for adjusting the load on the mill rolls by the screwdowns during mill operation. Such device, however, does not provide for rapidly advancing and retracting of the screwdowns when the work rolls are to be changed and is unsatisfactory for automatic changing of the mill rolls. A proposal has been made to overcome these difficulties as shown in Trapp Patent No. 3,164,044; there spacer blocks are positioned between the screwdowns and the chocks. This proposal, however, requires the removal of the spacer blocks for each retraction of the screwdowns and is an added operation to be facilitated for automatic roll changing.

The present invention overcomes these disadvantages and provides an efficient and simple way of rapidly advancing and retracting the screwdowns.

I provide a lift for rapidly advancing and retracting the screwdowns of a rolling mill. Preferably the lift is comprised of at least one worm shaft meshing with worm gears capable of driving the screws of the screwdowns. First power means are provided to drive the worm shafts at high speeds with relatively low torque. Means for coupling said first power means to said worm shaft are provided. Second power means capable of driving said ICC worm shaft at low speed and high torque and a drive train connecting said second power means to the worm shaft including a speed reducing means and a clutch, said clutch being operable to interrupt the transmission of power from said second power means through the speed reducing means to the worm shaft. Preferably the speed reducing means are gear means concentrically positioned on the worm shafts and are capable of freely rotating on the worm shafts or capable of being rigidly connected to the worm shafts through first clutch means. The gear means are capable of driving the worm shafts at relatively low speed with relatively high torque. The gear means are driven either separately or in unison by a second power means.

I prefer that the worm shafts be positioned on a com mon axis and be coupled by a second clutch means so that the worm shafts can be driven in unison by the first power means having one or more motors and gear train. I further prefer that the second power means consist of two motors which have their shafts positioned on a common axis and coupled by a third clutch means so that the gear means can be driven separately or in unison.

In operation, the first clutch means is disengaged and the second clutch means is engaged when the screwdowns are being rapidly advanced or retracted. The first clutch means is engaged and the second clutch means is disengaged when the mill rolls are to be loaded and to adjust the load on the mill rolls during mill operation.

Other details, objects and advantages of my invention will become apparent as the following description of the present preferred embodiment thereof proceeds.

In the accompanying drawings I illustrate a presently preferred embodiment of my invention in which:

FIGURE 1 is a top view of a screwdown-lift;

FIGURE 2 is a side view of the screwdown-lift shown in FIGURE 1 with portions broken away to line IIII of FIGURE 1; and

FIGURE 3 is a partial side view of the screwdownlift shown in FIGURE 1 taken along line IIIIII of FIGURE 1 showing the first clutch means.

Referring specifically to the drawings, a screwdownlift is comprised of worm shafts 2 positioned on a common axis and having worm teeth 3 thereon. The worm teeth 3 mesh with worm gears 4 which are keyed to the shafts of screwdowns 6 so that the worm shafts 2 drive the screwdowns 6. Each screwdown 6 has a screw 7 which advances and retracts from a screwdown nut 8 as the shaft 5 of the screwdown 6 is driven. Each screwdown nut 8 is rigidly fixed in the housing 9 of the screwdown 6. The worm shafts 2 are coupled by a magnetic clutch means 10 so that the worm shafts 2 can be driven separately or in unison by power means 11 at relatively high speeds with relatively low torque. Gear means 12 are concentrically positioned on the end portions of worm shafts 2. Clutch means 13 which may be electrically or hydraulically operated are positioned on end portions of worm shafts 2 and are capable of rigidly coupling gear means 12 to worm shafts 2. Gear means 12 are driven by motors 14 through pinions 15. Motors 14 have their shafts 16 positioned on a common axis and are coupled by clutch means 17 which may be electrically or hydraulically operated so that the motors 14 can drive the worm shafts 2 separately or in unison at relatively low speeds with relatively high torque.

Each hydraulic actuated clutch means 13 is provided with sliding gear means 18 which engages inner gear means 19 and outer gear means 21. Each inner gear 19 is rigidly affixed to a worm shaft 2. Each outer gear means 21 is rigidly affixed to a gear means 12. Each hydraulic actuated clutch means 13 is operated by activating double acting hydraulic cylinders 23 and in turn engaging and disengaging a sliding gear means 18 from an outer gear means 21 through a linkage 24. In the case of the hydraulic actuated clutch means positioned between power means 11 and one of the worm shafts 2, sliding gear means 18 also engages inner gear means 20 at all times, and inner gear 20 is rigidly atfixed to drive shaft 22. Drive shaft 22 is driven by power means 11. When power means 11 is actuated, sliding gear means 18 is thereby driven.

In operation, rapid advancing of screwdowns is accomplished by actuating hydraulic cylinders 23 to cause clutch means 13 to disengage gear means 12 from worm shafts 2 and by engaging magnetic clutch means 10 so that worm shafts 2 are driven in unison. Thereafter power means 11 is started so that worm shafts 2 rotate at relatively high speed with relatively low torque and in turn worm gear 4, shaft and screw '7 of the screwdown 6 rotate at relatively highspeed with relatively low torque. Loading and adjusting of the load on the mill rolls by the screwdowns 6 is accomplished by actuating hydraulic cylinders 23 to cause clutch means 13 to engage gear means 12 with worm shafts 2 and by disengaging magnetic clutch means so that worm shafts 2 can be driven separately or in unison. Thereafter m0- tors 14 are actuated as needed separately by disengaging electric or hydraulic actuated clutch means 17 or in unison by engaging electric or hydraulic actuated clutch means 17.

The arrangement of motors and connections described herein permits the primary motor to readily tolerate the inactive auxiliary motor at low r.p.m.s during the small worm shaft screwdown adjustments and disconnects the primary motor 14 and gearing 12 and during high speed operation of the auxiliary motor to protect the auxiliary motor against the overload of the inertia of the primary motor and gearing.

While I have shown and described a present preferred embodiment and use of the invention, it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied within the scope of the following claims.

I claim:

1. In a rolling mill having rolling mill rolls arranged in a housing and roll adjusting means including screwdowns having screws for adjusting the rolls, a screwdown-lift for advancing and retracting the screwdowns of the rolling mill comprising at least one worm shaft drivingly connected to the screws of the screwdowns, first power means capable of driving the worm shaft at relatively high speed with relatively low torque, means for coupling said first power means to said worm shaft, second power means capable of driving said worm shaft at relatively low speed and high torque, and a drive train connecting said second power means to the worm shaft including a speed reducing means and a clutch, said clutch being operable to interrupt the transmission of power from said second power means through the speed reducing means to the worm shaft.

2. A rolling mill according to claim 1 wherein the screwdown-lift comprises two worm shafts positioned on a common axis and coupled by a second clutch means whereby the worm shafts can be driven in unison by the first power means.

3. A rolling mill according to claim 1 wherein the second power means has shafts positioned on a common axis and coupled by third clutch means whereby the gear means can be driven in unison by the second power means.

4. A rolling mill according to claim 1 wherein the first and second power means are separate motor means.

5. A rolling mill according to claim 4 wherein said clutch is operable between the speed reducing means and the worm shaft to disconnect the same.

6. A rolling mill according to claim 5 wherein said speed reducing means includes gearing concentric with said worm shaft, said clutch means being operable to disconnect said concentric gearing from the worm shaft.

7. A rolling mill according to claim 4 wherein said worm shaft is coaxial with the worm shaft of at least one other screwdown-lift, and including clutch means for coupling said worm shafts for simultaneous driving thereof at high speed during operation of said first motor means.

8. A rolling mill according to claim 4 wherein said first motor means remains coupled to said worm shaft during operation of said second motor means.

References Cited UNITED STATES PATENTS 1,951,875 3/1934 Laabs 74-661 2,972,916 2/1961 Morgan 74-661 XR 3,127,790 4/1964 Howey 74661 3,164,044 1/1965 Trapp 72243 3,213,711 10/1965 Vandenkieboom 74661 XR ARTHUR T. MCKEON, Primary Examiner US. Cl. X.R. 74661, 665 

